There are known ECUs (Electronic Control Units) in a vehicle to communicate with each other to thereby perform various controls in the vehicle smoothly. Therefore, the introduction of the power line communication (PLC) system is considered. This power line communication system is a technology which superimposes signals on high frequency carriers to thereby transmit and communicate.
For instance, Patent Literature 1 describes a technology where a moving object is equipped with a balanced feeder line composed of two parallel wire lines. The balanced feeder line is in proximity of a coupler shaped of a loop. Thereby, the moving object and the balanced feeder line form an electromagnetic induction connection (i.e., coupling) therebetween.
[Patent Literature 1] JP-A-2005-45327
The inventors find the following. The above known technology enables electromagnetic induction connection and transmission of electric power and signals; however, there is much leakage flux in other than connection portions which transmit and receive the electric power and the signals. In addition, when a system environment changes, a communication quality may deteriorate to make it difficult to maintain high speed communication.